With rapid development of mobile communications technologies, functions of a terminal product become increasingly diverse, and product dimensions tend to be compact, which impose a harsher and stricter requirement on a terminal antenna. At present, LTE (Long Term Evolution) products have gradually been put into commercial use, and some terminal products are also required to support an LTE frequency band. Because a bandwidth of the LTE frequency band is much broader than that of a 2G (the second generation mobile telecommunications technology) frequency band and that of a 3G (the third generation mobile telecommunications technology) frequency band. The LTE frequency band (698 MHz to 960 MHz, 1710 MHz to 2690 MHz) imposes a new requirement on a bandwidth of an antenna. A conventional antenna cannot satisfy a requirement for a sufficient bandwidth. In addition, because LTE communications imposes a quite high requirement on the antenna, antenna efficiency (a ratio of power radiated by an antenna to active power input into the antenna, where a numerical value of the ratio is constantly less than 1) cannot be too low (at least greater than 35% at the frequency band of 698 MHz to 960 MHz, and at least greater than 45% at the frequency band of 1710 MHz to 2690 MHz).
In the prior art, a structure of a terminal antenna is shown in FIG. 1, where 101 is a PCB (printed circuit board), 102 is an antenna pattern, and 103 is a signal feed-in point. The signal feed-in point is a connection point of an antenna and a connection point of a radio frequency circuit to feed in or feed out a signal. A size of the antenna is further reduced by means of printing the antenna on the PCB, but the power of the antenna is low and the bandwidth is narrow. Still further, a radio frequency circuit with an antenna may implement double resonance of a high frequency and a low frequency by adding a matching circuit, which may increase a resonance point, but cannot improve efficiency of the antenna, and also restricts improvement of the bandwidth.